Reverse over-ride system for mower traction drive

Abstract

A reverse over-ride system is provided for a mower traction drive having a front pair of hydraulic traction motors and a rear pair of hydraulic traction motors. Each motor is operable in a forward direction or a reverse direction, and each front motor is in series with a rear motor. The system includes a solenoid operated valve connected to each rear motor. Each solenoid operated valve has a first position in which a check valve opens to allow recirculation through the rear wheel motors while the mower operates in a forward turn, and closes to disallow recirculation so the rear wheel motors may build pressure and drive during hill climbing. Each solenoid operated valve has a second position allowing free rotation of the rear motor while the machine operates in a reverse direction. A mechanical or electronic linkage is provided between the reverse pedal and solenoid operated valves.

1 . A reverse over-ride system for a mower traction drive, comprising:
 a front pair of hydraulic traction motors and a rear pair of hydraulic traction motors, each motor operable in a forward direction or a reverse direction, each front motor being in a series hydraulic circuit with a rear motor;   a solenoid operated valve connected to each rear motor and having a first position allowing recirculation through a rear motor while the front motor drives in a forward direction during turns, and a second position allowing free rotation of the rear motor while the front motor drives in a reverse direction; and   a linkage between a reverse pedal and the solenoid operated valves.   
   
   
       2 . The reverse over-ride system of  claim 1  wherein the linkage between the reverse pedal and the solenoid operated valves includes a reverse switch mechanically linked to the reverse pedal. 
   
   
       3 . The reverse over-ride system of  claim 2  wherein the mechanical linkage includes a rod. 
   
   
       4 . The reverse over-ride system of  claim 1  wherein the linkage between the reverse pedal and the solenoid operated valves is electronic. 
   
   
       5 . The reverse over-ride system of  claim 1  wherein each solenoid operated valve includes a poppet valve. 
   
   
       6 . A reverse over-ride system for a mower traction drive, comprising:
 a reverse pedal movable between a normally disengaged position and an engaged position;   a linkage between the reverse pedal and a pair of solenoid operated valves that are actuated if the reverse pedal is in the engaged position;   actuation of the solenoid operated valves allowing free rotation of a pair of rear wheel hydraulic traction motors.   
   
   
       7 . The reverse over-ride system of  claim 6  further comprising a check valve to selectively permit recirculation through the pair of rear wheel hydraulic traction motors if the solenoid operated valves are unactuated. 
   
   
       8 . The reverse over-ride system of  claim 6  wherein each rear wheel hydraulic traction motor is in a series hydraulic circuit with a front wheel hydraulic traction motor. 
   
   
       9 . The reverse over-ride system of  claim 6  wherein each rear wheel hydraulic traction motor is in a parallel hydraulic circuit with the other rear wheel hydraulic traction motor. 
   
   
       10 . The reverse over-ride system of  claim 6  wherein the linkage is mechanical and includes a reverse switch. 
   
   
       11 . The reverse over-ride system of  claim 6  wherein the linkage is electronic. 
   
   
       12 . A reverse over-ride system for a mower traction drive, comprising:
 a hydraulic circuit directing hydraulic fluid to a pair of front wheel hydraulic traction motors and a pair of rear wheel hydraulic traction motors;   a reverse pedal movable from a disengaged position to an engaged position; and   the reverse pedal connected to a pair of solenoid operated valves such that moving the reverse pedal to the engaged position moves the solenoid operated valves to a position allowing the hydraulic fluid to bypass the pair of rear wheel hydraulic traction motors.   
   
   
       13 . The reverse over-ride system of  claim 12  wherein moving the reverse pedal to the disengaged position moves the solenoid operated valves to a position allowing hydraulic fluid to recirculate through the pair of rear wheel hydraulic traction motors during turns. 
   
   
       14 . The reverse over-ride system of  claim 12  wherein the reverse pedal is mechanically linked to a reverse switch. 
   
   
       15 . The reverse over-ride system of  claim 14  wherein the reverse switch is actuated by a return to neutral mechanism. 
   
   
       16 . The reverse over-ride system of  claim 12  wherein the reverse pedal is electronically linked to the solenoid operated valves.